Forming die



A. ILLSCHE FORMING DIE Filed Sept. 27, 1941 Feb. 1, 1944.

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Patentecl FeB. 1, 1944 UNITED STATES PATENT OFFICE FORMING:DIE

Arthur I1sche, Bye, N. Y. Application September 27, 1941, Serial No.412,594 1 Cla irn. (cl. 7 -90) The invention relates to forming dies forscrewthreading blanks of sheet metal or other material offrustro-conical and other forms. While the invention is adaptable formaking either member of a pair of screw-threading dies and substantiallythe same method is employed in producing them, it will not be necessaryto descrbe both and the desoription wil] accordingly be limited to themaking of the female die.

Heretofore, the difiiculties encountered hav made it practicallyinipossible to make female forming dies for screw-threadng small blanks,particularly blanks of tapered form of the size usedas fasteners fordetachably securing buttons to garments or for womens hand-bags andvarious other purposes, where the over-all dimension of the iastenerdoes not exceed a half or three-quarters of an inch in any direction.The main difficulty met with results from the lack of space for theoperation of a cutting or other tool in the smallend of the tapered diesocket, in which the thread of the socket must be extended to make thedie effectve for its intended purpose. As the space mentioned isinsufficient to accommodat-e the smallest workable tool, theimpossiblity of cuttirug a thread of any appreciable depth andparticularly a deep thread, which requires a 1arger, strenger tool, willbe apparent.

Recognizing the impracticability of milling or otherwise cutting thethread of the female die, the thread is pre-formeel by the present invention, as a separate element, for insertion in the socket, of the dieblock in which it may be permanently or removably secured.

In carrying my improved method into effect, a. helix is produced bywinding a strip of heatsoftened meta1 or other suitable materia1, edgeon, on a former, which may or may not be helically grooved to receivethe strip. The cross sectional form of the strip is such that whencoiled, as described, it presents within the helix, a counterpart of thethread to be ormed by the die on the blanks. The helix thus prepared, isthen removed from the former and after being finished and hardened, ifrequired, is fitted, seated and secured in the socket of the de-block orhelder, ready for use.

While the former on which the strip is wound, may be smooth surfaced, itis preferably helica1ly grooved to receive the strip and the crosssectional form of the groeve corresponds, in counterpart, to thatportion of the strip that enters the groove.

In order to solid1y seat the helix in the socket of the die-block orholder, the strip is given such width that the overlapping turns of thehelix form a square or other shaped thread exterorly thereof, which isfitted to aseat of counterpart format ion within the socketed die-block.and either permanently 01 removably secured, as

above stated.

The cross sectional shape of the strip and the groove in the former maybe varied to prbduce any form of thread desired and the former maylikewise be varied from uniform diameter throughout, to any degree oftaper required by the blanks to be threaded.

The accornpanying drawng wil1 serve to illustrate means suitable forcarryingthe invention into effect but I do not wish to be understood asintencling to limit myself to either the exact-form or details shown, asvarious changes may be made therein without departing from the spiritand scope of the invention, as outlined in the appended claim.

In the dravving- Fig. 1 illustrates the method of prcducing a taperedhelical thread.

Fig. 2 is a view in side elevation of the finished thread.

Fig. 3 is a vertical centra] section, showing the helicai thread seatedand secured in a die-block or holder the bore of which is indicated indotted lines and Figs. 4:, 5 and 6 show different cross sectional formsof the strip to produce different threads.

Referring now to the drawing, I, represent, diagrammatically, anysuitable or well known clampng means, or securely holding the former 2and the strip 3, to be wound thereon. T0 simplify the illustration, theformer and the strip are shown held by a, single clamping means but itwill be understood that they may be separately and independently held, ifound more convenient in carrying out the operation of producng thehelix.

In its preferred form, the former 2, is sub stantially a duplioate ofthe male die that cooperates with the fema1e die in the threadingoperation, being here shown as frustoconical and provided with a helicalthread 4, that ex tends from the base to the apex. The former 2, ingeneral outline, follows the shape of the blanks to be threaded, whichmay be of uniform diameter or tapered to different degrees to meet therequirements of the use for which they are designed. While the groove ofthe thread. on the former 2 is of material aid in the winding operation,in receiving the shaped edge portion of the strip and spacing theturnsapart as required, a smeeth surfaced fermer may be effectively empleyed,if desired, by giving the strip the requred cross sectional shape tespace the turns of the thread apart and permit the strip te be closelywound on the former.

The strip 3 is erdinarily made of steel and is annealecl er heat isapplied te seften it as it is being wound on the fermer but any othersuitable meta1 may be empleyed, ifpreferred. The cross sectional shapeof the strip cerresponds, in ceunterpart, te the thread te be formed enthe blanks and may be varied, as illustrated in Figs. 4, 5 and 6, tepreduce any form of thread desired.

When helically ceiled, as shown in Fig. 2, that portion of the strippresented inside of the helix, is an exact ceunterpart of the threadedfermer on which it was wound.

The helix thus produced is removed frem the former and after beingreduced te the required length and hardenecl and pelished, is seated andeither permanently er remevably secured in a die-bleek er helder 5,whichis secketed at 6 as shewn in Fig. 3, te receive the same.

In order te seat the helix firmly and securely in the secket, the stripfrom which it is fermed, is given suiicient width te prodnce anoverlapping efifect in the turns, exterierly of the helix, ferming asquare or other shaped thread 'l, which extends throughout its length. Aceunterpart formatien 8, in the secket 6, is provided as a seat for thetluead.

T0 permanently secure the helix in the socket of the die-bleek, it isordinarily spot-welded er brazed and When it is te be removably secured,a. set-screw is employed, as indicated at .2 in Fig. 3.

In the use of a ceoperating pair of the dies, they are axially aligned,ene above the ether and nermally spaced apart a sufficient distance teprovide clearance for a strip of sheet metal er ether material te be fedstep by step between them. The blanks te be threaded are pressed up,spun er etherwise preformed at equi-spaced points on the strip and thestep by step feed of the latter brings the blanks thereon successivelyin axial alignment with the dies. Assuming a blank te be thuspositioned, the dies, rotating in eppesite drections, are advancedtowards each ether and engage the blank interiorly and exterierlythereef and bycombined pressure and spinning actien, shape the blank andcause it te conform te the epposing faces of the dies. The retatien ofthe dies is then reversed and they move away frem each ether te clearthe formed blank and permit the strip te be advanced a step te bring anew blank into pesitien fer the next eper"ation.

HaVing descrbed my invention, I claim:

The female member of a oeperating pair of dies fer forming by spinningand pressure action a screw thread in frustre-cenical blanksof sheetmetal and ether materals, consisting of a helically weund strip ofhardened material of frustreconical form terminating at the smaller endshort of the center of the helix te previde an opening threugh which theend of the blank is ferced as the dies ceme tegether te give the threadformeel by the die a rounded entering point, the

inner edge of the strip presented within the helix being shaped in crosssection te conform in counterpart to the cross section of the threadtobe fe1med by the die, and. a. helder provided at one end with a secketin which the helix is seated and removably secured and in which thestrip is of such width that the turns of the helix overlap and projectsufficiently beyend each other te form a helical shoulder exterorly ofthe helix and the socket in the helder is of counterpart fermatien toprovide a seat fer the shoulder.

ARTHUR ILLSCI-IE.

